The present invention relates to the collection and evaluation of materials such as eggs from the piscine species (i.e., fish) and, more particularly to a fistula device and method used in such collection and evaluation.
In sturgeon culture, the currently accepted practice is to perform multiple surgical biopsies, annually, on individual fish to evaluate and collect eggs for spawning. These procedures are, understandably, extremely traumatic for the fish. The use of repeated surgical procedures causes increased trauma, pain and stress to the fish while increasing the risk of infection and contamination of samples that are collected in this manner.
Fistulas have been designed for use with cattle which allow external access to the rumen of the animal to permit removal of ingesta. A further fistula of interest is the subject of U.S. Pat. No. 5,993,485 (Beckers). This patent discloses a bladder portal including a fistula threaded on the inside to accept a seatable screw. The fistula includes a flange fitting inside the bladder and a further flange positioned outside the body. The screw is removed to permit urine to flow. U.S. Pat. No. 4,265,244 (Hill) discloses a tubular stoma adapter for insertion into the lumen of a body orifice. The adapter is held in place by tabs formed at the outer edge of a circular lip and by an adhesive sheet which holds the taps against the walls of the corresponding wall of the patient. U.S. Pat. No. 3,313,289 (Kapral) discloses a chamber for implantation into the body cavity of an animal. The chamber comprises a ring having two faces and a pair of membranes which cover the ring faces.
In accordance with the invention, a method and device are provided which enable less traumatic in-vivo evaluation of egg development within fish, and which thereby enable more efficient and less traumatic collective of roe for hatching or marketing as a consumable. The device of the invention can also be used to provide access to the ceolomic cavity for other types of sampling (i.e., biopsies of other organs, sperm collection, and the like). The device can be used by individuals involved in fish production or by researchers in fish physiology, theriogenology and medicine.
In accordance with a first aspect of the invention, a fistula device is provided for use with piscine species to gather material from inside an exterior body wall of the species, the device comprising: a body member including a flange at one end thereof adapted to engage an outside surface of the exterior body wall of the piscine species and a hollow cylindrical body portion including internal threading and external threading; a retaining ring adapted to be placed against an interior surface of the exterior wall of the species, the ring including internal threading permitting the ring to be screwed onto the external threading of the body member; a mesh member secured to retaining ring and adapted to be sutured to the exterior wall of the species internally of that wall; and a removable member including a threaded portion adapted to be screwed into the hollow body portion of said body member.
Preferably, the flange of said body member includes a plurality of holes spaced around the circumference thereof for enabling the flange to be sutured to the exterior wall of the species.
Advantageously, the retaining ring includes a plurality of holes spaced around the circumference thereof and a plurality of sutures received in the holes for affixing the mesh member to the ring. The mesh member advantageously comprises a knitted monofilament mesh, and is preferably made of polypropylene.
The member advantageously includes a flange at one end thereof.
In accordance with a second aspect of the invention, a method is provided for collecting materials from inside of a piscine species through an exterior body wall of the species, the method comprising: providing a fistula device comprising a hollow body member having a flange at one end thereof, a retaining ring having a mesh member affixed to the outer periphery thereof and a closure plug; placing the body member in a hole created by excision of skin and muscle tissue in a lateral or ventral aspect of the exterior body wall of the species, and positioning the flange of the body member against an exterior surface of the body wall of the species; placing the retaining ring inside the species through a second incision in the body wall and securing the ring to the body member; affixing the mesh member to an interior area of the body wall; and inserting the closure plug into hollow body member to close off the body member.
Preferably, the ring is threaded onto external threads on the hollow body member to secure the ring to the body member. Similarly, the closure plug is preferably threaded into an internally threaded central bore in the body member.
Advantageously, the flange of the body member is sutured to the exterior surface of the body wall of the species to provide further stability.
The mesh member is preferably affixed to the body wall by suturing the mesh member to the interior area of the body wall.
Further features and advantages of the present invention will be set forth in, or apparent from, the detailed description of preferred embodiments thereof which follows.